The present invention relates generally to valves located in underground fluid-carrying conduits and more particularly to tools used to operate said valves.
Underground fluid-carrying conduits, such as water lines, fuel lines, sewer lines and the like, typically have gate valves installed at periodic locations. In this manner, one may shut off the flow of the fluid through a desired length of the conduit by closing selected gate valves. Examples of conditions that require closure along particular segments of the conduit include, but are not limited to, emergency conditions (e.g., a water main break or gas leak) and construction projects (e.g., tapping the water system for a new building into a preexisting underground water main).
Referring now to FIG. 1, there is shown a gate valve which is well-known in the art and which is identified generally by reference numeral 11. Gate valve 11 includes a shortened conduit 13 that is shaped to define first and second openings 15-1 and 15-2 that are in fluid communication with one another. A movable gate (not shown), which is typically rounded or rectangular in shape, is located within conduit 13 between first and second openings 15-1 and 15-2 and serves to regulate the flow of fluid therebetween.
The gate is typically connected to a vertically disposed stem 17 which at least partially protrudes out from conduit 13. An enlarged operating nut 19 is traditionally mounted onto the free end of stem 17, operating nut 19 typically having a square shape in both longitudinal and lateral cross-section. In this manner, it is to be understood that fluid flow through valve 11 can be manually regulated through the rotation of operating nut 19 (i.e., clockwise rotation to close valve 11 and counterclockwise rotation to open valve 11).
Because gate valves are commonly disposed a considerable distance underground (e.g., often several feet beneath the surface of a road), an elongated wrench is commonly used to turn operating nut 19. In this manner, the valve can be easily regulated through a relatively small access hole in the ground, which is highly desirable.
Referring now to FIG. 2, there is shown one well-known type of wrench which is often used to turn operating nut 19, the wrench being identified generally by reference numeral 21. Wrench 21 is typically constructed out of a strong, rigid and durable material, such as cast iron or steel, and comprises a square-shaped key 23 which is connected to an elongated T-bar 25 through an inverted U-shaped stirrup, or strut, 27.
As can be seen, key 23 is constructed as an elongated band that is configured so as to define a square-shaped central opening 24 therein. It is to be understood that key 23 is sized and shaped to fittingly receive operating nut 19 within opening 24.
T-bar 25 comprises an elongated arm 29 which is connected to key 23 through stirrup 27, with arm 29 preferably being several feet in length. An orthogonally disposed handle 31 is formed onto the free end of arm 29 so as to provide T-bar 25 with its T-shaped design. Although T-bar 25 is represented herein as being generally square-shaped in lateral cross-section, it is to be understood that T-bar 25 is often circular or rectangular in lateral cross-section as well.
In use, wrench 21 is commonly used to operate an underground gate valve 11 in the following manner. Specifically, key 23 of wrench 21 is disposed through a small access hole (either preexisting or newly created) in the ground directly above the gate valve 11 to be regulated. Due to the considerable length of arm 29, key 23 can be disposed several feet below ground by an operator who remains above ground. By grasping handle 31, the operator orientates key 23 such that operating nut 19 inserts into opening 24. Because key 23 and operating nut 19 have complementary square-shaped designs, it is to be understood that operating nut 19 fits loosely within key 23. With nut 19 positioned within key 23 as described above, the user manually rotates T-bar 25 using handle 31. The rotation of handle 31 similarly rotates operating nut 19 in such a manner so as to open and/or close gate valve 11.
A gate valve may sit underground for many years, even decades, without being turned. As a result, it has been found that an infrequently operated gate valve often becomes stuck or otherwise difficult to regulate (e.g., due to the accumulation of dirt, grime or other similar forms of debris between moving parts). Accordingly, in order to move a stuck gate valve, an operator is typically required to rotate the wrench handle back and forth a number of times to loosen the gate mechanism of the valve. Because the operating nut often fits rather loosely within the wrench key, this process of loosening the gate mechanism commonly causes the wrench to round (i.e., strip) the operating nut. With the operating nut rounded, it is to be understood that a conventional gate valve wrench (e.g., of the type shown in FIG. 2) is no longer able to adequately grip the operating nut and thereby regulate the gate valve.
The inability to operate a gate valve using a traditional gate valve wrench introduces a number of notable shortcomings.
As a first shortcoming, the inability to operate a gate valve using a traditional gate valve wrench often necessitates that the access hole in the ground be significantly expanded so as to permit a worker and/or large machinery to reach the rounded operating nut. This expansion of the access hole is extremely costly due to the significant amount of labor and machinery required to excavate. In addition, the expansion of the access hole is rather time consuming and disruptive in nature.
As a second shortcoming, the inability to operate a gate valve using a traditional gate valve wrench creates a potentially dangerous condition. Specifically, because a more expansive and time-consuming process is required to rotate the rounded nut, hazardous conditions that require an immediate shut-off of selected gate valves (e.g., a gas leak or water main break) can remain untreated for unacceptably long periods.
Accordingly, in U.S. Pat. No. 7,036,402 to J. S. Marks et al. (hereinafter the '402 patent), there is disclosed a water main T-bar that is configured to work in combination with a socket tool, the combination forming a key for actuating an underground valve in a water main, sewer line, gas line, petroleum pipeline, fuel line, etc. In the '402 patent, it is suggested that the socket tool may be of the type shown in U.S. Pat. No. 6,928,906 to J. S. Marks (hereinafter the '906 patent). The socket tool disclosed in the '906 patent features spring loaded pins that adapt or conform to the valve stem, handle or nut shape and size. The pins are bundled in parallel inside a housing and collectively gain purchase on and apply the torque necessary to open or close the valve. In this manner, the socket tool may be used in conjunction with the T-bar to actuate a gate valve with a decayed operating nut.
Although well known in the art, the water main T-bar and adaptor disclosed in the '402 and '906 patents suffer from a couple notable shortcomings.
As a first shortcoming, the self-forming socket disclosed in the '906 patent is rather mechanically complex in nature, thereby rendering it considerably expensive to manufacture and purchase. Due to the high cost associated with such sockets, most municipalities are limited in the number of self-forming sockets that they can purchase. As a result, it has been found that certain emergency situations which require the immediate shut-off of selected gate valves are unacceptably delayed until operators can locate and acquire the socket and complementary T-bar.
As a second shortcoming, the self-forming socket disclosed in the '906 patent is not designed for attachment to a traditional water main T-bar. Rather, the self-forming socket is designed for attachment with the T-bar disclosed in the '402 patent. As a result, municipalities that are to consider use the socket disclosed in the '906 patent are additionally required to purchase a new T-bar, thereby increasing expenses.
As a third shortcoming, the self-forming socket disclosed in the '906 patent is relatively large in size. As a result, the socket is often incapable of being passed through many preexisting access holes in the ground. Consequently, a time-consuming and expensive excavation process is often required to expand the size of the access hole.
As a fourth shortcoming, the self-forming socket disclosed in the '906 patent has been found to be ineffective when used to turn operating nuts that are considerably round in lateral cross-section. Specifically, it has been found that the parallel pins are unable to effectively grab an operating nut that does not include at least one flattened surface.
As a fifth shortcoming, the self-forming socket disclosed in the '906 patent is often difficult to use in certain conditions. Most notably, when disposed underground, dirt and rocks have been found to accumulate within the socket and can compromise the ability of the spring-biased pins to be displaced.